Medium
S.54 on Glow-worm Ultimate3 Combi

Your boiler is temporarily waiting because it has detected that the water pressure is too low or the water is not circulating between the radiators and the boiler correctly.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Book a service

This fault should be looked at by a Gas Safe engineer within the next week or two. It may get worse if left.

What the manual says

Manufacturer manual

Waitingperiod:Lowwaterpressureinthecircuit(flow/returnspreadtoolarge)

From this model's manual
Verified against the Glow Worm Ultimate3 Combi installation & service manual, page 45.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

DIY fix possible

Check the pressure gauge on the front of your boiler; if it is below 1.0 bar, you need to top it upLocate the filling loop (usually two silver taps connected by a braided hose) underneath the boilerOpen the taps slowly to let water in until the needle reaches 1.5 bar, then turn both taps off tightly

Find a Gas Safe engineer
Search the official register →
Boiler cover options

Avoid the next call-out bill

A cover plan would handle faults like S.54: no call-out fees, no surprise bills.

Approved partner
Domestic Appliance Guard
Unlimited call-outs, 24/7 helpline, no price-hike promise
Get a quote →

Affiliate links. We may earn a commission at no extra cost to you.

Related fault codes

F.22View →F.73View →F.75View →

Related guides you might find useful

Boiler keeps losing pressure

Six most common causes of dropping pressure.

Read →

Low pressure — repressurise guide

Step-by-step using the filling loop.

Read →

Banging / kettling / whistling noise

Each noise points to a different fault.

Read →